Chemical nickel plating on nonmetallic materials



Sept. 28, 1954 G. GUTZEIT rs1-A1.'

CHEMICAL NICKEL PLATING ON NONMETALLIC MATERIALS Filed June 7, 1951 .25. mnwo E Sum :s m NIS il Q D Initiation Time, Minutes @GESU QE @NS mm .Nm

Initiation Time, Minutes INVENToRs Gregoire Gutzeit BY Wil/iam J. @f ehan Abraham Krieg Affys.

Patented Sept. 28, 1954 UNITED STATES PATENT OFFICE CHEMICAL NICKEL PLATING ON NON- METALLIC MATERIALS Application June 7, 1951, Serial No. 230,352

9 Claims.

The present invention relates to processes of chemical nickel plating of non-conductive and non-'catalytic solid materials and to methods of preparing the surfaces of su-ch materials so that a homogeneous and adherent nlm of nickel may be chemically deposited thereon.

In the copending application of Gregoire Gutzeit and Abraham Krieg, Serial No. 194,656, iled November 8, 1950, now Patent No. 2,658,841, granted November 10, 1953, there is disclose-d a process of chemically plating with nickel, metals and other catalytic materials, by contacting the materials with an acid bath containing nickel ions and hypophosphite ions and a buffer. This process is carried on under certain optimum conditions, which are as follows:

The ratio between nickel ions and hypophosphite ions in the bath, expressed in molar concentrations, is within the range from 0.25 to 0.60; the absolute concentration of hypophosphite ions in the bath expressed in mole/liter, is within the range from 0.15 to 0.35; the absolute concentration of the buler in the bath is approximately equivalent to two carboxyl groups for every nickel ion that can be deposited, for instance, in the case of sodium acetate, 0.120 mole/liter of acetate ion; the initial pH of the bath is within the approximate range from 4.5 to 5:6; the temperature of the bath is slightly below the boiling point thereof, about 98 centigrade; and the ratio between the volume of the bath, expressed in cubic centmetros (cm), and the surface area of the material that is to be plated expressed in square centimetres (cm), (V/A) is not greater than 10. The buffers mentioned in that application and employed in the tests therein referred to are soluble salts of simple short chain aliphatic monocarboxylic acids with an ionization constant pKa, higher than 4.7; such as, acetic acid, butyric acid, propionic acid, etc.

In the copending application of Gregoire Gutzeit and Ernest J. Ramirez, Serial No. 204,424, filed January 4, 1951,11ow Patent No. 2,653,842, granted November 10, 1953, there is disclosed a process of chemically plating with nickel, metals and other catalytic materials, by contacting the materials with an acid bath containing nickel ions and hypophosphite ions and an exaltant. This process is carried on under certain optimum conditions, which are as follows:

The ratio between nickel ions and hypophosphite ions in the bath, expressed in molar concentrations, is within the range from 0.25 to 1.60; the absolute concentration of hypophosphite ions in the bath, expressed in moles/liter, is within the 2 range 0.15 to 1.20; the absolute concentration of the exaltant in the bath is approximately equivalent to two carboxyl groups for every nickel ion that can be deposited, for instance, in the case of sodium succinate, at least 0.05 mole/liter of succinate ion; the initial pH of the bath is within the approximate range 4.3 to 6.8; the temperature of the bath is slightly below the boiling point thereof, about 99 centigrade; and the ratio between the volume of the bath, expressed in cm, and the surface area of the material that-is to be plated, expressed in cm?, (V/A), is not greater than 10. The exaltants mentioned in this last mentioned application and employed in the tests therein referred to are soluble salts of simple short chain aliphatic dicarboxylic acids with an ionization constant pKz higher than 5.4; such as malonc acid, succinic acid, glutaric acid, etc.

In the applications referred to, it was pointed out that the catalytic materials that could be plated with nickel employing the baths and processes set forth were materials which cause the plating reaction:

C317. zmzronzeon Nie n surf.

2 Hro Ni H2 For instance, using nickel chloride to provide the nickel ion and sodium hypophosphite to provide the hypophosphite ion:

(2) l cat. 2Na(H2P Oz) 21120 -l- NiCl' Slll In other words, materials that catalyze the oxidation of the hypophosphite ion to the phosphite ion, while reducing water to atomic hydrogen, and, at the same time, promoting the formation of molecular hydrogen comprise catalytic materials. This reaction can be ascertained by observing and measuring the volume of hydrogen gas evolved in an aqueous solution of a soluble hypophosphite upon addition of the catalytic material, preferably at the highest possible temperature below the boiling point of the solution. The following elements are catalytic: Cu, Ag, Au, Be, B, Ge, Al, Tl, Si, C, V, Mo, W, Cr, Se, Te, Ti, Fe, Co, Ni, Pd and Pt; and the following elements are definitely noncatalytic: Bi, Cd, Sn, Pb and Mn.

Nonconductive and noncatalytic materials, such as plastics, hard rubber, wood, ceramics, etc do not cause the plating reactions (l) and (2) and thus cannot be plated with nickel directly in accordance with the processes set forth in the applications mentioned.

v Accordingly, it is the general object of the present invention to provide a process of chemical plating with nickel the surfaces of non-conductive and non-catalytic materials, such as plastics, hard rubber, wood, ceramics, etc.

Another object of the invention is to provide a method of preparing the surface of a non-con ductive and non-catalytic material of the character mentioned so that it may be chemically plated with nickel.

A further object of the invention is to provide a method of preparing the surface of a nonconductive and noncatalytic material so that it may be chemically plated with nickel employing substantially ther improved processes described in the applications mentioned above.

These and other objects and advantages of the present invention will be understood from the foregoing and the following description taken with the accompanying drawings, in which:

Figure l shows the variations in the initiation time interval of nickel plating upon prepared non-catalytic samples with variations in ratios of nickel ions `to hypophosphite ions in the chemical nickel plating baths containing sodium salts; and

Fig. 2 shows the variations in the initiation time interval of nickel plating upon prepared non-catalytic samples with Variations in ratios of nickel ions to hypophosphite ions in chemical nickel plating baths containing calcium salts.

In accordance with the present invention, in order to obtain nickel chemical plating of nonconductive and non-catalytic materials, such as plastics, hard rubber, wood, ceramics, etc., it is necessary first to prepare or condition the sur face of the material prior to contacting it with the chemical nickel plating bath. More particularly, the surface of the material is modified so as to form thereon firmly anchored growth nuclei. It is not necessary to achieve a complete coverage of the surface of the material with the growth nuclei, as the nickel plating will spread for a certain distance from each growth nucleus in the two dimensions along the surface of the material as it builds up in the third dimension upon the growth nucleus, thereby obtaining ultimately a complete and homogeneous coating of nickel upon the surface of the material. Also, the surface of the material is modified to eliininate polarization of the areas between the growth nuclei. by effecting the presentation in these areas of a fresh surface.

In one form of the method, the surface of a nonconductive and nonoatalytic mate ial of the character referred to may be prepared for chemical nickel plating by freshening and contaminating it with traces of a catalyst in such a manner that the catalytic particles are securely anchored in place upon the freshened surface. By simply dusting the surface with a finely divided catalytic powder, such as aluminum, carbon, etc., a coating is provided so that nonconductive and noncatalytic material of the character mentioned is prepared for chemical nickel plating. However, in order to obtain good adhesion of the subsequently deposited nickel to the material, the catalyst must be firmly anchored to the surface of the material and the surface of the material must be fresh; whereby as many growth nuclei as possible are securely anchored to the surface of the material, and the noncatalytic areas on the surface of the material are not polarized. These conditions may ordinarily be obtained by removing the surface skin of the material as the catalyst is enibebbed in the freshly presented surinstance, liquid honing with Vapor Blast ec infface of the material. While the catalytic powder may take the form of any one or comb' the catalytic elements previously ment from a practical standpoint nickel, copper, r. carbon and aluminum, as well as the alloys br and bronze, have been found to be moet useful. Specifically, beryllium cannot be used in the presence of an acetate buffer in the nickel. plating bath as an insoluble `acetate is formed; iron has a tendency to rust rapidly, gold and ve are too expensive, etc.

In another form of the method where an artificial or compounded non-conductive catalytic material is produced by forming, ing or casting, the catalyst may be mixed the basic material prior to forming, etc. A .1, the amount of catalyst present at the surface ofthe formed material is useful, enough catalyst should be added to the basic material initially to provide adequate growth nuclei at the boundary or surface of the formed material. The formed. material is subsequently prepared by sario blasting, brushingl tumbling, chemical etc etc., to expose a fresh surface thereon prior to being Lsubjected to the nickel plating bath. instance, by compounding a thermosettinCT gia.n molding powder (e. g. Bakelite), with ali ninuin powder, by weight, molding the compound under heat and pressure, then subjecting the article thus formed of the compound to a ne abrading action by liquid honing in order to prepare the surface thereof, and, finally, chemically nickel plating the prepared surface of an excellent adherent and continuous nickel coat-- ing may be obtained.

ment using Novaculite 325 or i250 mesh abrasive mixed with 10% aluminum powder has been found to be excellent in the preparation of the surfaces of materials for chemical nickel pla' Also, dry blasting with 325 mesh emery p.,4 and 5% of chemically reduced nickel has l found to be useful in the preparation of the surfaces of the materials; the saine is true with activated sanded surfaces obtained by powde the sand belt with a catalyst, such as chen1 reduced nickel in powder form.

In a still further form of the method, surface of a non-conductive and nome-ata material may be prepared for chemical nickel plating by freshening the surface of the by mechanically employing one of the abres techniques mentioned and then by contamining the freshened surface with a noncata substance in powdered form to provide the gre nuclei on the freshened surface of the mater the non-catalytic substance constituting a nencatalytic metal whose solution potential is great-- er than that of nickel, such, for example, as manganese, zinc, magnesium and cadmium. In other words, by depositing on the freshened surface of the noir-conductive and non-catalyst material, ne particles or a thin nlm of a metal less noble than nickel, an ion replacement occurs in the chemical nickel plating bath between the nickel ions and the atoms of the less noble metal, whereby the nickel replaces the less noble 'metal and then acts as a catalyst. In the plating reactions (1) and (2), the advantage of this form of the method resides in the fact that soft less noble metals, such as zinc and cadmium, are easy to apply since these metals with low melting points can be flame-sprayed upon the freshened surface of the material. On the other hand, the more brittle, less noble metals, such as manganese, are more amenable to dusting upon the freshened surface of the material. rIhe solution potential of nickel is about 0.25; and the following less noble metals have higher solution potentials: Mg, Al, Mn, Zn, Cr, Ga, Fe and Cd. The elements A1, Cr, Ga, and vFe are catalytic themselves, and the solution potentials of the other elements are: Mg, 2.34, Mn, 1.05, Zn, 0.76, and Cd, 0.40.

The following tests show the application of this form of the method. Bakelite samples were cut to the dimensions of 2 inches X 3A; inches and activated, i. e., the glossy surface skin was removed by means of fine emery paper which had been rubbed, respectively, with solid pieces of zinc, magnesium and cadmium. In the case of manganese, the plastic samples, after freshening, were dusted with the metal powder and rubbed by hand. Each of these samples was then placed in 50 cubic centimeters of a chemical nickel plating bath containing 0.07 mole/ liter of nickel chloride, 0.225 mole/liter of sodium hypophosphite and 0.02 mole/liter of sodium succinate. The initial pH of the bath was adjusted to 5.1 with HCl and the bath was heated to 93 C. The time necessary to initiate nickel plating for Mn, Zn, Mg, and Cd were respectively 0, 6 minutes, 8 minutes and 30 minutes. Two of the samples, after 60 minutes, in the cases of Zn and Mn, had good uniform nickel platings on the surfaces thereof; and the samples after 60 minutes, in the cases of Mg and Cd, had fair nickel platings on the surfaces thereof. Thus, it may be concluded that manganese and zinc give optimum results when employing this form of the method.

In the preparation of the surface of the nonconductive and noncatalytic material, it is usually advisable just preceding the transfer of the material to the chemical nickel plating bath to subject the surface thereof to a standard cleaning operation, using techniques familiar to the metal working trade which will not deactivate the surface, such for instance as spray washing with a detergent, vapor degreasing, etc. llihis final standard cleaning step is unnecessary and may be omitted when the surface of the material is prepared or activated by certain of the steps described above, including liquid honing and steam blasting, since these steps will usually affect the necessary standard cleaning or degreasing simultaneously with the activation or preparation of the surface of the material.

In accordance with the process of the present invention, after the surface of the non-conductive and non-catalytic material has been activated or prepared in accordance with the method described above, the material is transferred to the chemical nickel plating bath in order that the plating of the nickel on the surface thereof is first initiated and then continued. The chemical nickel plating bath employed may be that disclosed in either of the previously noted applications; however, in employing either of these baths, it is advantageous to use a bath composition having a nickel ion to hypophosphite ion ratio toward the lower extremity of the range set forth, as it has been discovered that such lower Ni++/(II2PO2) ratio baths initiate lthe nickel plating upon the previously activated or prepared surface of the non-conductive and non-catalytic material in an appreciably shorter time interval than do the higher Ni++/ (I-IzPOzV ratio baths.

In this connection, it will be apparent that once nickel platingvon the surface of the material has been initiated, i. e., proceeded to a point where the surface thereof is covered with a continuous film of nickel, even a monomolecular layer, the conditions with respect to continued nickel plating become identical to those prevailing in the plating of catalytic materials as disclosed in the said applications previously mentioned. In other words, a different state exists only at the beginning of the chemical nickel plating reaction in the case of a nonconductive and non-catalytic material having a previously prepared or activated surface. Moreover, it has been discovered that the best conditions for obtaining a rst uniform and continuous flash of nickel plating upon the previously prepared or activated surface of the non-conductive and non-catalytic material are somewhat different from the best conditions for obtaining continued nickel plating of the surface after the flash layer of metallic nickel has been obtained. Thus, it will be understood that after the flash coating of nickel upon the surface of the material has been obtained, the material may be transferred to one of the previously mentioned baths having a higher Ni++/(H2PO2) ratio, in order to continue the plating of the nickel upon the flash coating of nickel deposited upon the surface of the material, although this transfer is not essential and is suggested only when it is desired to obtain a rather thick nickel coating in a minimum time interval.

Accordingly, it will be understood that the following considerations pertain to the composition of chemical nickel plating baths that are provided specifically for the purpose of initiating the nickel plating upon the previously prepared and activated surface of a non-conductive and non-catalytic material, it being desirable to initiate the flash coating of nickel in the minimum time, time intervals of ten minutes, or less, being preferable In a general way, it can be stated that the less stable the chemical nickel plating bath is, the faster it will initiate the nickel plating of the previously prepared or activated surface of the nonconductive and non-catalytic material. In other words, the more the chemical nickel plating bath tends toward chemical non-selective random reduction of nickel ions, as shown by thermal decomposition tests or by the early appearance of black precipitate during plating, the faster the chemical nickel plating bath will initiate. However, the presence of black precipitate ordinarily causes a rough deposit of metallic nickel upon the material undergoing the plating operation, as well as a rapid depletion of nickel ions in the bath by autocatalytic decomposition. Therefore, it is necessary to obtain in the chemical nickel plating bath that is employed for initiating the flash deposit of the nickel upon the material, a compromise between stability and the time interval lag to achieve the initiation mentioned.

Considering rst a vbath of the general char- 7 acter of that disclosed in the previously mentioned application of Gutzeit and Krieg, when alkali compounds are used as reagents, the buffer being a salt of a short chain aliphatic monocarboxylic acid, such as sodium acetate, the optimum concentration of the hypophosphite ions derived from alkali hypophosphite is again between 0.15 and 0.35 mole/liter. The initiation time is practicaily a straight line function of the ratio of nickel ions to hypophosphite ions, but relatively large amounts of black precipitate are formed at the lowest Ni++/(H2PO2) ratios, although the quality of the plating is still good within the optimum range of l\li++/(H2PO2)* of 0.25 to 0.60. The following tabulation summarizes tests run in 50 cc. of chemical nickel plating bath at a V/A ratio of 2.5 on aluminum activated general purpose Bakelite samples; the absolute concentration of hypophosphite ions derived from sodium hypophosphite was 0.224 mole/liter; the buffer was sodium acetate and its concentration in acetate ions was 0.120 mole/liter; and the initial pH was adjusted to 4.85:

When using alkaline earth salts both as a buffer and as a source of hypophosphite ions, it is possible to obtain good nickel plating and small amounts of black precipitate by selecting the optimum ratio of `l\li++/(H2l0z) at the proper initial pH. The results of these tests are illustrated by the Curve 20 in Fig. 2; and it will be 0bserved that the plating results were excellent at a nickel ion to hypophosphite ion ratio of 0.433, with an initiation time of only 5 minutes, and that only a mere trace of black precipitate was formed during the nickel plating operation. In referring to alkaline earths, we include magnen sium.

Finally, considering a chemical nickel plating bath of the general character of that disclosed in the previously mentioned application of Gutzeit and Ramirez, the bath containing an exaltant in the form of a salt of a short chain aliphatic dicarboxylic acid, such as sodium succinate, the bath is extremely stable, and will initiate nickel plating upon an activated or prepared noncone ductive and noncatalytic material only after a The results of these tests are illustrated by the curve E0 in l; and it will be observed that amount of nickel reduced chemically at random (as opposed to catalytic plating) is largest at the lower Ni++/(H2PO2)* ratios, while initiation time and coverage are best with these lower ratios.

Considering another chemical nickel plating bath or the general character of that disclosed in the previously mentionad application of Gutzeit and Krieg, when alkaline earth compounds are used as reagents, the buffer being a salt of a short chain aliphatic monocarboxylic acid, such as calciun acetate, the optimum concentration of the hypophosphite ions derived from alkaline earth hypophosphites is again between 0.15 and 0.35 mole/liter. The initiation time is much shorter, although it is still a function of the l-li++/(.'rl2PO2) ratio. The following tabulation summarizes tests run in 50 cc. of chemical nickel plating bath at a V/A ratio of 2.5 on aluminum activated general purpose Bakelite samples-g the absolute concentration of hypophosphite ions derived from calcium hypophosphite was 0.224 mole/ liter; the buier was calcium acetate and its concentration in acetate ions was 0.112 mole/liter; and the initial pil was adjusted to 4.85. In these tests, the nickel plating was carried on for 180 minutes after initiation; and the results were as follows:

long period of time. The following tabulation summarizes tests run in 50 cc. of chemical nickel plating bath at a V/A ratio of 2.5 on aluminum activated general purpose Bakelite samples; the absolute concentration of hypophosphite ions was 0.225 mole/liter; the exaltant was sodium succinate and its concentration in succinate ions was 0.06 mole/liter; the ratio of Niift/(HlPOQ- was 0.4; and the tests were continued for 60 minutes after initiation of plating occurred. The results were as follows:

plating at low pI-I values with a bath of the character of that disclosed in the previously mentioned application of Gutzeit and Ramirez, a slight modication is suggested. This consists in 9 the use of a lower Ni++/(H2PO2) ratio in the bath, in the range 0.25 to 0.3.

The herein disclosed process of producing an intimately bonded and continuous layer of nickel upon the surface of a solid non-metallic body involving exposing a fresh non-polarized surface of the body having incorporated therein and exposed thereon dispersed growth nuclei minute carbon particles is disclosed and claimed in the copending divisional application of Gregoire Gutzeit, William J. Crehan and Abraham Krieg, Serial No. 370,142, filed July 24, 1953.

From the foregoing, it is apparent that a process has been provided for the platingwith nickel of nonconductive and noncatalytic material, such as plastics, hard rubber, wood, ceramics, etc., that involves the preliminary activation or preparation of the surface of the material employing the present method so as to provide thereon firmly anchored growth nuclei and nonpolarized areas accommodating the initiation of the flash nickel coating on the material. Moreover, in carrying out the process of the present invention after activation or preparation of the surface of the material in accordance with the method of the present invention, an intimately bonded and uniform layer of nickel may be obtained upon the surface of the material having any desired thick- It will be understood that the invention is not limited except as defined by the appended claims.

We claim:

l. The process of producing an intimately bonded and continuous layer of nickel upon the surface of a solid non-metallic body, which comprises exposing a fresh non-polarized surface of said body having incorporated therein and exposed thereon dispersed growth nuclei minute particles essentially comprising an element selected from the group consisting of iron, cobalt, nickel, aluminum, copper, silver, gold, palladium and platinum, and immersing said body in a bath consisting essentially of an aqueous solution of a nickel salt and a hypophosphite during a suflicient tirne interval to cause initial nickel plating upon said growth nuclei and subsequent growth of the nickel plating into a continuous nickel upon the fresh non-polarized surface of said body.

2. The process of producing an intimately bonded and continuous layer of nickel upon the surface of a solid non-metallic body, which comprises exposing a fresh non-polarized surface of said body, securing to the fresh non-polarized surface of said body dispersed growth nuclei minute particles essentially comprising an element selected from the group consisting of iron, cobalt, nickel, aluminum, copper, silver, gold, palladium and platinum, and immersing said body in a bath consisting essentially of an aqueous solution of a nickel salt and a hypophosphite during a sufficient time interval to cause initial nickel plating upon said growth nuclei and subsequent growth of the nickel plating into a continuous nickel layer upon the fresh non-polarized surface of said body.

3. The process of producing an intimately bonded and continuous layer of nickel upon the surface of a solid non-metallic body, which comprises abrading the surface of said body to expose a fresh non-polarized surface thereof, securing to the fresh non-polarized surface of said body dispersed growth nuclei minute particles essentially comprising an element selected from the group consisting of iron, cobalt, nickel, aluminum,

copper, silver, gold, palladium and platinum, and immersing said body in a bath consisting essentially of an aqueous solution of a nickel salt and a hypophosphite during a sufficient time interval to cause initial nickel plating upon said growth nuclei and subsequent growth of the nickel plating into a continuous nickel layer upon the fresh non-polarized surface of said body.

e. The process of producing an intimately bonded and continuous layer of nickel upon the surface of a solid non-metallic body, which comprises abrading the surface of said body with an abrasive material having dispersed therein minute particles essentially comprising an element selected from the group consisting of iron, cobalt, nickel, aluminum, copper, silver, gold, palladium and platinum as both to expose a fresh non-.polarized surface of said body and to embed in dispersed relation therein said minuts particles as growth nuclei, and immersirlg said body in a bath consisting essentially of an aqueous solution of a nickel salt and a hypophosphite during a sufficient time interval to cause initial nickel plating upon said growth nuclei and subsequent growth of the nickel plating into a continuous nickel layer upon the fresh non-polarized surface of said body.

5. The process of producing an intimately bonded and continuous layer of nickel upon the surface of a solid non-metallic body, which comprises abrading the surface of said body with minute nickel particles so as both to expose a fresh non-polarized surface of said body and to embed in dispersed relation therein said minute nickel particles as growth nuclei, and immersing said body in a bath consisting essentially of an aqueous solution of a nickel salt and a hypophosphite during a sufficient time interval to cause initial nickel plating upon said growth nuclei and subsequent growth of the nickel plating into a continuous nickel layer upon the fresh non-polarized surface of said body.

6. The process of producing an intimately bonded and continuous layer of nickel upon the surface of a solid non-metallic body, which comprises exposing a fresh non-polarized surface of said body, securing to the fresh nonpolarized surface of said body dispersed growth nuclei minute particles essentially comprising an element that is less noble than nickel, and immersing said body in a bath `consisting essentially of an aqueous solution of a nickel salt and a hypophosphite during a sufficient time interval to cause initial nickel plating by displacement with respect to said growth nuclei and subsequent growth of the nickel plating into a continuous nickel layer upon the fresh non-polarized surface of said body.

7. The process of producing an intimately bonded and continuous layer of nickel upon the surface of a solid non-metallic body, which comprises exposing a fresh-non-polarized surface of said body, securing to the fresh non-polarized surface of said body dispersed growth nuclei minute particles essentially comprising an element selected from the group consisting of manganese, zinc, magnesium and cadmium, and immersing said body in a bath consisting essentially of an aqueous solution of a nickel salt and a hypophosphite during a suicient time interval to cause initial nickel plating by displacement with respect to said growth nuclei and subsequent growth of the nickel plating into a continuous nickel layer upon the fresh non-polarized surface of said body.

8. The process of producing a composite solid body of non-metallic material having an intimately .bonded and continuous layer of nickel upon the surface thereof, which comprises compounding With said non-metallic material an element selected from the group consisting of iron, cobalt, nickel, aluminum, copper, silver, gold, palladium and platinum, fabricating said body of said compounded non-metallic material and said element, exposing a fresh nonpolarized surface of said body so that said element is dispersed as growth nuclei minute particles at the fresh non-polarized surface thereof, and immersing said `body in a bath consisting essentially of an aqueous solution of a nickel salt and a hypophosphite during a suiiicient time interval to cause initial nickel plating upon said growth nuclei and subsequent growth of the nickel plating into a continuous nickel layer upon the fresh ynon-polarized surface of said body.

9. The process of producing a composite solid body of synthetic plastic material having an intimately bonded and continuous layer of nickel upon the surface thereof, which comprises compounding with said synthetic plastic material an element selected from the group consisting of t iron, cobalt, nickel, aluminum, copper, silver, gold, palladium and platinum, fabricating said body of said compounded synthetic plastic material and said element, exposing a fresh nonpolarized surface of said body so that said element is dispersedas growth nuclei minute particles at the fresh non-polarized surface thereof, and immersin-g said body in a bath consisting essentially of an aqueous solution of a nickel salt and a hypophosphite during a suicient time interval to cause initial nickel plating upon said growth nuclei and subsequent growth of the nickel plating into a continuous nickel layer upon the fresh non-polarized surface of said rbody.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,128,059 Schoop Feb. 9, 1915 1,149,974 Chisholm Aug. 10, 1915 2,351,940 Dupuis June 20, 1944 2,430,581 Pressel Nov. 1l, 1947 2,532,283 Brenner et al Dec. 5, 1950 

1. THE PROCESS OF PRODUCING AN INTIMATELY BONDED AND CONTINUOUS LAYER OF NICKEL UPON THE SURFACE OF A SOLID NON-METALLIC BODY, WHICH COMPRISES EXPOSING A FRESH NON-POLARIZED SURFACE OF SAID BODY HAVING INCORPORATED THEREIN AND EXPOSED THEREON DISPERSED GROWTH NUCLEI MINUTE PARTICLES ESSENTIALLY COMPRISING AN ELEMENT SELECTED FROM THE GROUP CONSISTING OF IRON, COBALT, NICKEL, ALUMINUM, COPPER, SILVER, GOLD, PALLADIUM AND PLATINUM, AND IMMERSING SAID BODY IN A BATH CONSISTING ESSENTIALLY OF AN AQUEOUS SOLUTION OF A NICKEL SALT AND A HYPOPHOSPHITE DURING A SUFFICIENT TIME INTERVAL TO CAUSE INITIAL NICKEL PLATING UPON SAID GROWTH NUCLEI AND SUBSEQUENT GROWTH OF THE NICKEL PLATING INTO A CONTINUOUS NICKEL LAYER UPON THE FRESH NON-POLARIZED SURFACE OF SAID BODY. 